Due to the risk of infection by pathogens, such as airborne pathogens, the use of protective facemasks has become part of standard practice in many settings, such as in hospitals and other medical facilities, by those who come into contact with patients. Protective facemasks are also widely used by others, such as medical professionals and other healthcare workers, for example, paramedics and emergency medical technicians, who interact with patients outside formal treatment settings. Typically, a facemask is worn by the medical professional or other healthcare worker to protect both the wearer and patient from transmission of any infective agent. For example, the facemask can be used to protect a healthcare worker from an infected patient. Likewise, the facemask can be used to protect a vulnerable patient from exposure to pathogens, for example a patient undergoing a surgical procedure or an immunocompromised patient. As such, protective facemasks are an essential component of a healthcare worker's personal protective equipment. Of course, it may also be beneficial for certain patients or individuals who are immunocompromised or particularly susceptible or vulnerable to infection to also wear such protective facemasks. Protective facemasks may also be useful for distribution to the general public in cases of epidemics or pandemics, as well as in cases of any widespread release of pathogens or agents containing pathogens, whether intentional or unintentional. An effective facemask represents a critical barrier in preventing the transmission of harmful infections.
Various designs and configurations for facemasks have been previously proposed. One class of masks uses a filter network to trap the pathogens. These facemasks include the surgical type masks commonly worn in hospitals. One example is described in U.S. Pat. No. 7,044,993 to Bolduc entitled “Microbicidal air filter.” Bolduc discloses a system that employs an immobilization network of fibers having antimicrobial agents incorporated and molecularly bonded into its structure. Another class of masks include those that employ filter canisters to trap the pathogens. One example is described in U.S. Pat. No. 6,681,765 to Wen entitled “Antiviral and antibacterial respirator mask.” Wen discloses a system that employs a filtration apparatus containing both an active stage and passive stage filter in the mask.
The aforesaid designs and other previously proposed facemasks suffer from a number of important shortcomings. For example, some designs may only immobilize and not neutralize the airborne pathogens. Thus, removal of a facemask after use may cause pathogens not completely immobilized to be dispersed into the air immediately around the user. The pathogen may cause an infection if inhaled or may pose a contact transmission risk via the hands during the disposal process. In addition, some of the designs incorporate viscous material into the filter material to capture particulate material, while other designs incorporate complex arrangements of filters inside cartridges. These designs may be impractical for use in facemasks. For example, they may be too complex and cumbersome to routinely use as well as too expensive. In other cases, material harmful to humans, such as fiberglass, iodine, or chlorine, are used as part of the filter medium. Another facemask design uses antibacterial agents that freely detach from fibers of the facemask. These designs have the problem of a rapid loss of their antibacterial activity upon cleaning or washing thereof.
As is apparent from the foregoing, all of the previously proposed techniques to retain and neutralize microbes are characterized to some degree by deficiencies. Accordingly, there is a considerable need for an improved antimicrobial facemask. In particular, there is a need for an antimicrobial facemask that is both effective, safe, comfortable, durable, easy to use and store and relatively inexpensive to produce.